AOPA and other industry groups are stepping up efforts to prevent incidences of jet fuel being contaminated with diesel exhaust fluid (DEF)—likely mistaken for fuel-system ice inhibitor—following an August event in which clogged fuel filters led to the failure of two of a business jet’s three engines, and several occurrences last year.
The bizjet, a charter operator’s Dassault Falcon 900EX, made a forced return to Florida’s Miami-Opa Locka Executive Airport after the crew received multiple clogged fuel filter warnings on departure, followed by failure of the trijet's No. 2 engine, according to a letter from the air charter company, alerting AOPA and others. A second engine failed during the return to the airport and the crew successfully completed an emergency landing with the remaining, No. 1 engine. The event’s duration from initial alert to landing was about 10 minutes, it said.
According to the SAIB, “DEF is a urea-based chemical that is not approved for use in jet fuel. When mixed with jet fuel, DEF will react with certain jet fuel chemical components to form crystalline deposits in the fuel system. These deposits will flow through the aircraft fuel system and may accumulate on filters, fuel metering components, other fuel system components, or engine fuel nozzles. The deposits may also settle in the fuel tanks or other areas of the aircraft fuel system where they may potentially become dislodged over time and accumulate downstream in the fuel system as described above.” The SAIB identified aircraft that “have experienced clogged fuel filters and fuel nozzle deposits that led to service difficulties and unplanned diversions.”
Aviation groups responded quickly and jointly to the recurrence.
“After this new incident, we feel a broader, collaborative approach is needed to help ensure another event doesn’t occur,” said David Oord, AOPA senior director of regulatory affairs. “Additionally, it is important for operators to be aware of the issue, and if a fuel filter light comes on, land as soon as practical and look for the possibility of DEF contamination. We are working with the FAA, NATA, National Business Aviation Association, and other stakeholders to provide additional education, awareness, and other measures to help prevent another DEF-contamination occurrence.”